1. Field of the Invention
This invention relates to the mixing of gases and liquids. More particularly, it relates to enhancing the dispersion of gases in liquids.
2. Description of the Prior Art
The dispersion of gases in liquids is an important feature of a wide variety of industrial operations. Thus, gases are dispersed in liquids for numerous gas dissolving, gas-liquid reaction and gas stripping of dissolved gas applications. As the gas is more finely dispersed in the liquid in the form of very small gas bubbles, the interfacial surface area between the gas and liquid is appreciably increased as compared to the surface area between the liquid and a like quantity of gas in the form of larger gas bubbles. In turn, an increase in the interfacial surface area between the gas and liquid is known to increase the mass transfer of the gas from the gas bubbles into the liquid, as well as the transfer of dissolved gas from the liquid into the gas bubble. Thus, by providing much higher interfacial area, all gas-liquid processes, such as gas dissolution, gas stripping and gas reactions between the gas phase and substances in the liquid phase will be improved.
The use of sonic shock waves to reduce the size of gas bubbles dispersed in a liquid is known in the art. Garrett, U.S. Pat. No. 4,639,340, discloses a particular technique directed particularly to the dissolving of oxygen in waste water. According to this technique, oxygen is uniformly dispersed in a waste water stream, which is then exposed to turbulent flow conditions and passed to a venturi for acceleration to a flow velocity in excess of the speed of sound in said gas-liquid mixture. A sonic shock wave is thereby created, and relatively coarse bubbles of oxygen are sheared into smaller bubbles by the turbulence resulting from the sonic shock wave.
Kiyonaga et al, U.S. Pat. No. 4,867,918, disclose an improvement comprising the combining of gas and liquid in close proximity to a venturi or other flow constriction means used to create supersonic flow velocities and subsequent deacceleration to subsonic velocity. Cheng, U.S. Pat. No. 4,861,352, discloses an in-line stripping method employing a venturi device and capable of accelerating at least a portion of the stripping gas or vapor/liquid composition to a supersonic velocity for the composition. In a further development, Cheng, U.S. Pat. No. 4,931,225, has disclosed a method and apparatus for dispersing a gas or vapor in a liquid in which the gas or vapor is injected into the liquid at a linear velocity which is sonic for at least a portion of said gas or vapor at the time of contact, with a composition comprising the liquid and said gas or vapor being caused to flow cocurrently with at least a portion of the composition being caused to flow at a linear velocity that is at least sonic.
Despite such useful advances, there remains a need and desire in the art for further developments to enhance the dispersion of gases in liquids. Such requirements pertain to gas-liquid processing operations in general, and are related to the continual desire in the art for improvement in industrial processing operations and to the reduction of equipment fabrication costs associated therewith. There is also a general desire in the art for a more efficient use of oxygen, nitrogen and other industrial gases in a wide variety of commercial applications in which industrial gases are presently employed or could be employed to improve current practice in the art. In particular, there is a desire in the art for in-line gas/liquid mixers having enhanced flexibility for use with a variety of gas/liquid mixing applications and operating conditions.
It is an object of the invention, therefore, to provide an improved process and system for the dispersion of gases in liquids.
It is another object of the invention to provide a process and system for enhancing the interfacial surface area between a gas and a liquid in which it is dispersed so as to enhance the mass transfer between such gas and liquid.
It is a further object of the invention to provide a process and system capable of enhancing the efficiency of gas-liquid dispersion operations and of providing operating flexibility with respect to various gas/liquid mixing applications and operating conditions.
With these and other objects in mind, the invention is hereinafter described in detail, the novel features thereof being pointed out in the appended claims.